By Sinéad Carew and Johann M Cherian

(Reuters) - Wall Street's main indexes rose on Tuesday, with the S&P 500 and the Dow closing at their highest levels in more than a month as investors assessed Donald Trump's first actions as U.S. president and were encouraged that he did not start his second term with blanket tariff increases.

Trump did not lay out concrete plans on the universal tariffs and additional surcharges on close trade partners as previously promised, but said he was thinking about imposing duties on Canadian and Mexican goods as early as Feb. 1.

While investors remain cautious about tariffs and the potential for a global trade war pushing inflation higher, brokerage Goldman Sachs lowered its forecast for the chances of a universal tariff this year to 25% from about 40% in December.

"There was a definite relief and a bit of surprise that tariffs weren't called out in the first round of executive actions that happened yesterday," said Carol Schleif, chief market strategist at BMO Private Wealth. "Markets are leaping to the conclusion, probably rightfully so, that the administration will take a more nuanced approach."

Investors hope the new administration will use the threat of trade levies as a negotiating tactic and take "a scalpel and not a sledgehammer to tariffs," Schleif said.

However, with trade policies still unclear, Schleif cautioned the market could face volatility if Trump puts out trial balloons on tariffs since the market has not had a 10% correction in a long time.